Base oil for cooling device, device-cooling oil containing the base oil, device to be cooled by the cooling oil, and device cooling method using the cooling oil

Abstract

A base oil for cooling a device contains a hydrocarbon compound at 30 mass % or more and exhibits a kinematic viscosity of 4 mm 2 /s to 30 mm 2 /s at 40 degrees C. The total number of a terminal methyl group(s) and a methylene group(s) in a main chain of the hydrocarbon compound is 16 or more. The total number of a methyl branch and an ethyl branch in the molecule is one or less. A device-cooling oil provided by blending the base oil is excellent in electrical insulation properties and thermal conductivity, and thus is favorably usable for cooling a motor, a battery, an inverter, an engine, an electric cell or the like in an electric vehicle, a hybrid vehicle or the like.

1 . A base oil for cooling a device, the base oil comprising 30 mass % or more of a hydrocarbon compound and exhibiting a kinematic viscosity of 4 mm 2 /s to 30 mm 2 /s at 40 degrees C., wherein:
 a total number of a terminal methyl group and a methylene group in a main chain of the hydrocarbon compound is 16 or more; and   a total number of a methyl branch and an ethyl branch in a molecule of the hydrocarbon compound is one or less.   
     
     
         2 . The base oil of  claim 1 , wherein a total number of the methylene group in the main chain is 16 or more. 
     
     
         3 . The base oil of  claim 1 , wherein the hydrocarbon compound comprises a chain structure. 
     
     
         4 . The base oil of  claim 1 , wherein the hydrocarbon compound comprises a saturated structure. 
     
     
         5 . The base oil of  claim 1 , wherein the hydrocarbon compound comprises an unsaturated structure. 
     
     
         6 . The base oil of  claim 1 , wherein a thermal conductivity of the base oil at 25 degrees C. is 0.138 W/(m·K) or more. 
     
     
         7 . The base oil of  claim 1 , wherein a volume resistivity of the base oil at 25 degrees C. is 10 13  Ω·cm or more. 
     
     
         8 . A device-cooling oil, comprising the base oil of  claim 1 . 
     
     
         9 . A device configured to be cooled by the device-cooling oil of  claim 8 . 
     
     
         10 . The device of  claim 9 , wherein the device is suitable for an electric vehicle or a hybrid vehicle. 
     
     
         11 . The device of  claim 9 , wherein the device is at least one selected from the group consisting of a motor, a battery, an inverter, an engine and an electric cell. 
     
     
         12 . A device cooling method comprising contacting the device-cooling oil of  claim 8  with a device. 
     
     
         13 . The device of  claim 10 , wherein the device is at least one selected from the group consisting of a motor, a battery, an inverter, an engine and an electric cell.